GB2333220A - Combined cultivator and seed sower - Google Patents

Abstract

A combined cultivator and seed sowing device comprising an array of sprung cultivator tines (3) have seed delivery coulters (6) located at their trailing edges. Soil is dislodged to cover the seedpath by a roller (8), such as a packer roller, which has relatively raised circumferential zones offset from the seedpath. Use of fine covering tines is avoided.

Description

AGRICULTURAL CULTIVATOR This invention relates to agricultural machinery and more particularly to agricultural cultivators, seed drills and coulters.

Before seed can be planted by farmers it is necessary to prepare the soil and a range of agricultural machinery is available for ploughing, harrowing and so forth. The cost of machinery and the time taken for each pass of a field is a significant economic factor for farmers. For autumn planting, when soil breakup through weathering is not available as it is over the winter for spring planting, traditional soil cultivation may involve up to twelve passes, the final stages being seed drilling and distribution. A final roll is preferred after seeding to firm the soil, enhancing soil-to-seed contact, discouraging slugs and, in some areas, press back stones that would otherwise interfere with and damage machinery in the eventual harvesting process. This traditional type of soil preparation routine is termed herein the 'soil preparation method' In order to reduce the number of passes required cultivation tools have been combined or made combinable so that several can be towed behind or mounted on a tractor in a single pass.

However, this approach has problems in that the resulting assembly is long and heavy, restricting manoeuvrability and requiring the tractor to carry counterweights.

Another approach that has been developed is to cut drills into previously unprepared soil. This usually has to be combined with prior chemical treatment of crop residue and the machinery required for such 'direct' drilling needs to be large and powerful. This generally makes the cost uneconomic except for the largest farms of thousands of acres, also the chemical treatment and resulting effects is not preferred by many farmers.

With both the soil preparation and the direct drilling methods a single pass of machinery forms a set of parallel drills for receiving seed, dispenses seed and covers the seed with soil. The depth of the drill is selected to suit the type and size of seed and may need to be, for example, less than 1 centimetre for oilseeds or several times that, say 5 to 8 centimetres, for peas or beans. Seed is delivered into the drills via a metering system that includes monitoring of the speed of travel over the ground and after seed delivery a tine flicks soil back over the seed.

In the soil preparation method the drills are formed by a coulter with a skid, disc or pushing part that makes the drill furrow as it is dragged over the ground and a dispenser that places the seed into the furrow. Following covering tines flick soil back into the furrow. Several, usually 24 to 32, coulters are individually mounted on arms to a main coulter bar across the span of the working path. The depth of the drill is controlled by helical springs usually on the individual coulter arms.

Two problems typically arise with this system. The first is that the design and mode of operation using helical springs gives a relatively light or low stiffness resiliance, typically equivalent to 5 kilograms, and as a result localised ground conditions can cause significant depth variation from each individual coulter arm. Upward bouncing is a particular problem.

This results in variation in germination and growth patterns which are detrimental to harvesting and yield. The second problem is that the covering tines which are relatively thin (typically 3 to 8 millimetres in diameter) wear rapidly, requiring frequent replacement, and also have a tendency to break When the ends of these tines break off, they are deposited in the field and their size is such that they often become the cause of punctures to tractor tyres in subsequent workings.

In the direct drilling method the drill is forcibly cut, literally by a rotational cutter or by a substantial, essentially rigid, vertical rod, for example of some 30 to 40 millimetres square cross-section that is gouged through the ground. Downward pressure of the order of 40 to 50 kilograms per coulter is typically applied. Height variation is not a problem in this power based system, but very powerful tractors are required and the same problems still arise with the covering tines. Attempts to downsize this system and combine it with some pre-cultivation have not been wholly successful as rigid in work rods, therefore of the same square and size cross-section, have been used and still require considerable power and weight to be forced through the soil as well as counterbalance of the tractor.

The present invention is directed towards solving these problems, combining seed delivery with a soil cultivation stage in a compact manner and eliminating the need for covering tines.

The invention is based upon seed delivery located at or closely behind the trailing edge of individual ones of an array of spring cultivator tines. Soil may be dislodged to cover the seed path by a roller having relatively raised portions offset from the seedpath.

According to the preferred aspect of the invention there is provided a combined cultivator and seed distributor comprising an array of vibrating in work cultivator tines, each tine having an associated seed distributor boot located proximate and rearward of its trailing edge for sowing seed in a seedpath, and a roller disposed rearwardly ofthe array of tines that has a spanwise series of relatively raised and recessed circumferential portions, the recessed portions being disposed (with reference to the intended travel direction) in alignment with respective ones of the tines and the raised portions being offset from such alignment.

The invention is now described by way of example with reference to the accompanying drawings in which: Figure 1 is a schematic side view illustrating an embodiment of the invention; and Figure 2 is a schematic view from above.

Referring to Figure 1, the main features of a preferred embodiment of the invention are shown schematically. Supporting structures of well known type are not illustrated. The soil surface designated by reference 1 will generally have been left by prior cultivation with a superficially rough surface that provides a greater surface area than an even surface. This is established good practice to maximise weathering or drying, allows more weed seed to germinate and also protects against erosion. The rough surface is smoothed by a levelling board or clod bar 2 and is then subjected to a cultivation process by rows of spring cultivator tines 3. The tines are of the general kind associated with a seed bed cultivation procedure and typically have a crosssectional diameter of 20 to 25 millimetres or around 10.x 30 millimetres rectangular section.

The tines are sufficiently robust to break up soil which they do by vibrating as a result of ground engagement. The spring of the tines is provided or assisted by a curved portion 4, which may have a variety of configurations for example a C or part spiral shape or S or other recurved shapes. It is important that the spring is stiff enough to vibrate in the required manner without too large amplitude, otherwise the required soil processing will not occur.

Likewise it must not be too rigid or vibration will not occur. The curved portion is usually of greater length than the lower end portion of the tine, with the curve extending above the mounting bar and ahead ofthe point of engagement with the ground. Commercially available spring tine assemblies of this general structure are available, for example the X-SEM from SICAM. The ends of the tine have replaceable shares and these ends can also have a variety of configurations, some being curved to cause more lifting of the soil.

For the purposes of the present invention a straight tip 5 is preferred as this vibrates with a significant lateral motion leaving a reasonably well defined furrow. Curved end tines dig in more, have more vertical motion and leave a less well defined furrow. The preferred straight end tine typically has approximately 5 centimetres rearward horizontal deflection of its point under a 14 kilogram load. More generally 3 to 7 centimetres at a load of 10 to 20 or 12 to 18 kilograms may be used, for example depending on the type of ground, although other ranges may be possible.

The tines are arranged in rows, typically three as shown, with the tines of the rows staggered from one another and for the purpose of the present invention so that only one tine traverses a particular path in the soil. Each row of tines is mounted on a laterally extending bar 10 (see Figure 2) or bar assembly which may have an overall span of the general order of 3 to 8 metres, wider spans being foldable for transportation. The lateral positioning of the tines across the width of its mounting bar is preferably adjustable to provide a facility to space the parallel tine paths over a range of spacings from approximately 10 to 30 centimetres, tines on an individual bar being spaced by three times that interval. (Other numbers of rows and variation in tine pattem would result in different spacing requirements.) For maximum spacing flexibility the bars are interlinked in pairs by cross rails 11 in a staggered formation.

As a tractor 12 (position shown in dotted outline) tows the apparatus in the direction ofthe arrow, the vibrating movement of the tines scratches out a shallow furrow into which seeds can be deposited. Each tine is provided with a seed distribution boot 6 which traverses immediately behind its respective tine. A particular suitable seed delivery system is a pneumatic feed in which seed is metered from a hopper in accordance with a ground speed sensing mechanism and blown along a series of distribution tubes to the coulter. Systems of this general type are readily available, for example the 'Accord' seed hopper and 'D.E.S.' distribution mechanism for supplying the prior art type of seed coulter. In the present invention seeds 15 may be delivered simply from an open ended boot 6 at the end of each distribution line or other ends adapted to prevent blocking, as are known, may be utilized. The boot is attached to its respective cultivator tine.

Travelling behind the rows of tines and coulters so that it engages the ground after seed delivery is a packer roller 8. The packer roller 8 has parallel sections of circumferentially distributed teeth 9 spaced apart by blank roller sections. The blank roller sections are scraped by a scraper blade to remove adhering earth in the usual known manner.

In the invention the packer roller performs three functions. It replaces the thin covering tines as the technique to cover the seeds, it performs a compacting fUnction thereby eliminating the need for separate rolling and it provides the height control for the tine assembly thereby controlling seed planting depth.

Seed cover is achieved by positioning the blank sections of the roller in line with the recess of the drill furrow, the teeth portions engaging the crests to dislodge and backfill soil over the seeds. Any scraped soil from the blank roller sections also covers the seeds. This interdigitating of the tinelseedpaths and packer roller teeth paths can be seen clearly in Figure 2. Controlling the tine assembly height by way of a roller regulates the height evenly over the whole span of the machinery independent of local ground conditions and is not subject to the excessive upward springy bounce experienced with helically sprung systems. The stiffness and arrangement of the tines is such that they are not subject to ground variation in a way that substantially alters the depth of furrow produced at a given roller height setting.

It will be appreciated that a significant difference between the direct drilling technique and the present invention is that the tines vibrate in work whereas the direct drilling rods are rigid in work. Much lower power and weight requirements make the system affordable to smaller farms.

There are in existence systems that include tine cultivators and rollers which can have a seed distribution system as an attachment. However, with these systems the seed coulter of the prior art type already described follows after the roller, usually as the final element and fUnctions to form the furrow and sow as described earlier. It has not previously been appreciated that the covering tines can be eliminated.

Using prior art drill attachments in combination with cultivators produces the problems of length of towed assembly, weight and need to counterbalance and additionally the seed hoppers are often mounted as close as possible to the tractor to help in weight balance resulting in them being inaccessible and difficult to fill.

In the present invention a seed hopper 13 is preferably mounted directly over the tine assembly which is close to the rear of the tractor. In this position, and due to the seed delivery at the tine locations, the length of the combined assembly remains short and manoeuvrable without the need for counterbalance. The hopper is also easily accessed from the rear of the assembly and can be filled directly from a dumper trailer 14 as shown schematically in dotted outline in Figure 1.

The individual elements may be modified to suit circumstances and different seed delivery mechanism may be used. In particular the packer roller may be replaced by a ridged roller or possibly other ground engaging means such as a levelling bar disposed generally spanwise or obliquely spanwise Although the pneumatic seed distribution system of the preferred embodiment has been described as of the generally available variety, a particularly preferred modification of this inlay be included in accordance with a preferred embodiment of the invention allowing the fan of the pneumatic system to be driven via gearing from the tractor drive shaft. The compact assembly of the present invention particularly lends itself to this arrangement which differs from existing systems which incorporate separate hydraulic drives.

Claims (9)

1. CLAIMS 1. A combined cultivator and coulter comprising an array of vibrating in work cultivator tines, each tine having an associated seed distributor located proximate and rearward of its trailing edge for sowing seed in a seedpath, and a roller disposed rearwardly of the array of tines that has a spanwise series of relatively raised and recessed circumferential portions, the recessed portions being disposed (with reference to the intended travel direction) in alignment with respective ones of the tines and the raised portions being offset from such alignment.
2. 2. Apparatus according to claim 1 in which the roller is a packer roller, circumferential zones having teeth comprising the raised portions and circumferential zones without teeth comprising the recessed portions.
3. 3. Apparatus according to claim 1 or claim 2 in which the cultivator tines include a curved spring portion located ahead of a ground engaging portion.
4. 4. Apparatus according to any preceding claim in which the sprung tines have a substantially straight ground engaging portion.
5. 5. Apparatus according to any preceding claim in which the seed distributors are attached to the trailing edge of their respective tine.
6. 6. Apparatus according to any preceding claim in which the seed distributors are fed from a pneumatic system.
7. 7. Apparatus according to claim 6 in which the pneumatic system has a fan drivable mechanically from a tractor output drive shaft.
8. 8. Apparatus according to any preceding claim in which the roller controls the height of the cultivator tines.
9. 9. Apparatus according to any preceding claim in which the tines exhibit a predominantly horizontal vibration in work.